1. Field
The invention relates to systems for solar heating and cooling of the interior air of houses and other buildings, and more particularly to those which store thermal energy and employ thermally induced circulation for thermal energy distribution within the building. Such systems, not using pumps or blowers, are called "passive."
2. State of the Art
Various passive systems have been utilized for solar heating of buildings, some involving heat storage masses, receiving and storing heat from sunlight admitted into the structure by glazed windows, and utilizing thermally induced circulation (siphoning) for interior distribution of air subsequently heated by the storage masses. Heat storage structures include masonry thermal storage walls, which include, for example, drums or bags of water to increase the thermal capacity. Such walls are generally used with a large glazed window and enclosing walls, called a solar greenhouse, to avoid convective heat loss. The enclosed space is generally not suitable for occupancy. Thermal storage walls are lacking means of adjusting the heat flow from the sun side to the opposite living space side. Time and degree of heating of the living space is uncontrolled. Similar disadvantage exists with thermal storage roofs or ceilings, and, quite massive roof or ceiling members are required for their support. Their elevated positions in the building causes thermal siphoning to be difficult to utilize. One attempt to do so is disclosed in U.S. Pat. No. 4,193,390, wherein complicated ducting is used for the purpose of reversing the natural, upward flow of heated air.
The prior use of pooled water as collector of solar energy is seen in U.S. Pat. No. 3,161,193, disclosing an isolated pool structure containing water heated through a glazed cover. It is not adapted for passive system, since the heated water must be pumped from the pool for use.
Other patents, not considered relevant to the present invention, but concerning passive solar heating systems include U.S. Pat. Nos. 4,000,851 and 4,089,142.
The light admitting windows have been insulated to prevent loss of interior heat energy from the solar mass during darkness or cloudiness. Louvers have been used, with temperature sensing controls. Styrofoam plastic beads have been blown into and out of double paned windows. The actuation systems for the specially fabricated, bulky insulated louvers, and the collection and forced air transport system for the beads, are complicated and expensive, and may therefore suffer from impaired reliability.